<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<style>
p{
    color: bisque;
    font-size: 20pt;
    text-align: center;
}

h1{
    color: black;


}



div{
    width: 300px;
    height: 300px;
    border-radius: 100%;
    background-color: cadetblue;
}
</style>

<body>
    <p>这是css应用于所有p标签</p>
    <h1>这是css应用于所有h1标签</h1>
    <div>这是css应用于所有div标签</div>
</body>
</html>